I got most of them from Game no Kanzume Otokuyou (J) [!]. The ROM was a 12-in-1 pack for some modified Genesis. The ROMs inside were compressed so I went ahead and cracked the compression. What's funny, that I got 14 games from it.

The Ristar and Sonic 2 are from Sonic Mega Collection+, PC version. Same thing, decompressed.